In a study published today in Nature, a University of Pittsburgh team found that eating creates a temporary metabolic state that influences the function of T cells –  immune cells that help the body detect and fight infection and disease, including cancer. In experiments in mice and humans, T cells collected after a meal showed a metabolic and functional advantage over those collected after fasting. The findings suggest that eating can have a lasting effect on how immune cells respond when they are activated –  a factor that could be relevant for T cell–based immunotherapies, such as CAR‑T cell therapy, as well as for responses to infection.